Paul McCartney abandons the guitar and pays homage to the music of his youth.John Lennon famously disdained Paul McCartney’s music hall tendencies as “nice little folk songs for the grannies to dig”. But the Beatles’ appeal owed as much to solid roots in Tin Pan Alley tunemanship as rock bite and experimentalism, lessons in classic song structure embedded in them from their parent’s generation.For his 35th post-Beatles album (counting Wings, classical, soundtrack and electronic works), McCartney pays homage to songs he first heard his father play on the family piano. The mood is of warm and cosy nostalgia, laced with the qualities of magic and emotion familiar from McCartney’s own works of whimsy. He loves this material, and it shows.